The present invention relates to an apparatus and a method for recycling bituminous material bodies by melting. In particular, the present invention relates to an apparatus and method for recycling bituminous composite material bodies comprising a composite material and a bituminous material. In particular, the apparatus and method are adapted for recycling roofing materials, in particular in the form of bituminous covering layers of roofing sheets.
The bituminous material bodies mentioned above for recycling usually have additional to a bituminous layer also possibly non-bituminous layers like a mineral covering layer or a bitumen reinforcement layer. Such bituminous material bodies, in particular roofing sheets or the like, are known from the prior art and are used in particular to cover and seal flat roofs e.g. For instance a bituminous layer can be provided as a conventional bitumen layer or as a polymer modified bitumen layer. The bitumen can in principle be oxidized or can be distilled bitumen. The reinforcement layer or other composite material can be a polyester fleece, fiberglass mat, fiberglass fabric or felt core.
After reaching the end of their service life, the roof sheets or other bituminous material bodies are usually processed for energy recovery, i.e. they are burnt as a substitute fuel in coal fire power stations. This kind of recycling causes considerable CO2 emissions and does not constitute full recycling of the roof sheets in the real sense aiming to a full material recycling.
Varieties of distillation bitumen and oxidized bitumen are basically in primary use nowadays to provide a bituminous layer in a bituminous material body. Bitumen as such is obtained by distilling crude oil. It consists of a mixture of different hydrocarbons and on account of its properties as one of the most used sealants in the construction industry. Distillation bitumen or refined bitumen usually refers to residual oil that remains after fractional distillation at reduced pressure and a temperature of approximately 350° C. These soft to medium-hard bitumen varieties are primarily used in road construction. Distillation bitumen may also refer to a high vacuum bitumen, which is obtained by further processing or further distillation of distillation bitumen under a vacuum. High vacuum bitumens, i.e. a special form of distillation bitumen, are mostly used for asphalt, floors, streets and rubber goods, due to their hardness and can also be used as distillation bitumens for a bituminous layer in a bituminous material body. Oxidized or blown bitumens are obtained by blowing air into distillation bitumen air at a temperature of approximately 250° C. Depending on this specific process used, it is possible to give the bitumen in roof specific properties in respect of resistance, to heat or cold.
On the other hand it has been found that hot processing and/or recycling of bituminous material bodies in principle can be achieved by melting the bituminous material bodies. However, a problem arises due to different melting or softening or transition points of temperature of the bituminous material in the bituminous material bodies on the one hand and the composite material in the material bodies or other residues on the other hand; usually the composite material and other residues can also comprise e.g. solid dirt, slate chippings and the like and these kind of composite material and other residues may remain solid when the bituminous material is already in a melted state.
In the prior art several attempts and suggestions have been made to handle bituminous material bodies for recycling by melting in an apparatus and a method; one of which is described for instance in WO 98/31519-A. As described therein the bituminous material bodies are heated such that the bituminous material melts. After that the bitumen and the other components forming the roofing materials are separated from each other. After sorting, reducing and melting, the material is sieved and sorted. This requires a comparable high amount of energy and is rather cumbrous.
Further in EP 11 44 171 B1 a method and apparatus has been described wherein the bitumen component of the bituminous material bodies—herein also referred to as the bituminous material—is melted in a vessel and separated from other non-melting components—herein also referred to as a composite material—of the bituminous material bodies. This is established by means of pressing or pushing together those non-melting components of composite material and all other residues in the vessel. The disclosure of the aforementioned patent EP 11 44 171 B1 herewith is incorporated in its entirety by reference into this application.
The basic principal of separating a bituminous material in the melted state from a composite material of a bituminous material body to be recycled as such has been found to be a good approach; however, still it remains to simplified and the apparatus and the method approach advantageously should be more efficiently to be handled. In particular the amount of energy and the separation process as such needs to be further improved.
EP 11 44 171 B1 provides a press means formed by a plate which is movable in the vessel over the bottom in the direction of a wall of the vessel which plate fits in cross section vertically in the vessel.
Further NL 1031868 describes an alternative approach wherein such plate is movable in the vessel in the vertical direction of a wall of the vessel wherein the plate fits in a cross section horizontal in the vessel. To prevent clogging of through flow orifices in the plate, the through flow orifices of the plate need to have a conical shape.
WO 02/28610 A1 describes a method and apparatus for the recycling of bituminous or tar containing materials, wherein these materials are separated from each other in a container by means of the application of a force onto the bituminous or tar containing materials such as a pressure force or a centrifugal force, which is brought to bear on the materials. In an embodiment, in the container, a base plate is formed and above the base plate, at a distance there from, a pressure plate is provided, which is movable along guiding elements in a direction towards and away from the base plate by means of a drive means. The base plate and the press plate can be provided with perforations or openings with varying diameter. The container is lowered down into a vessel, and the vessel is filled with a melting medium, which is liquid hot bitumen or hot fuel oil or another hot melting medium. The container with in it the rest materials that are pressed together in the form of a block is finally raised and lifted out of the vessel and the block can thereafter be handled as waste, for instance burnt.
Also these designs can be improved insignificantly.